Hi, I love this game! I've been following this series from the beginning.
I have an idea: I'm into futas, so what if you add a secret item? When used on your sister or other female characters, they become futas. You could also add a "PP+" option to make their PP bigger.
Additionally, if you implement a dating sim mechanic, the player could unlock a futa/male sex scene (if futa mode is activated). Or just astetics
And please add a character costumization feature(clothes,sun glasses,hat,..ect)
Thanks for everything!